U.S. patent number 10,008,322 [Application Number 14/746,163] was granted by the patent office on 2018-06-26 for filter assembly and method.
This patent grant is currently assigned to General Electric Company. The grantee listed for this patent is General Electric Company. Invention is credited to Ravindra Shyam Bhide, Lionel Durantay, Ajith Kuttannair Kumar, Vandana Rallabandi.
United States Patent |
10,008,322 |
Bhide , et al. |
June 26, 2018 |
Filter assembly and method
Abstract
An electronic filter assembly includes a magnetically conductive
annular body extending around a center axis, a set of magnetically
conductive prongs radially extending from the center axis toward
the annular body, and conductive windings extending around the
prongs. The conductive windings can be disposed around the prongs
instead of the annular body to assist in conduction of common mode
magnetic flux, to reduce impedance of the filter assembly, and/or
to more evenly distribute temperature in the filter assembly. A
method for forming an electronic filter assembly includes forming
an electronic filter assembly having a magnetically conductive
annular body extending around a center axis and a set of
magnetically conductive prongs radially extending from the center
axis toward the annular body. The annular body and the prongs can
be formed by coupling plural layers of magnetically conductive
bodies together.
Inventors: |
Bhide; Ravindra Shyam
(Bangalore, IN), Kumar; Ajith Kuttannair (Erie,
PA), Durantay; Lionel (Champigneulles, FR),
Rallabandi; Vandana (Bangalore, IN) |
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
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Assignee: |
General Electric Company
(Schenectady, NY)
|
Family
ID: |
55853418 |
Appl.
No.: |
14/746,163 |
Filed: |
June 22, 2015 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160125998 A1 |
May 5, 2016 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62069946 |
Oct 29, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F
27/28 (20130101); H01F 37/00 (20130101); H01F
41/0233 (20130101); H01F 27/263 (20130101) |
Current International
Class: |
H01F
27/28 (20060101); H01F 37/00 (20060101); H01F
27/26 (20060101); H01F 41/02 (20060101) |
Field of
Search: |
;336/65,83,170,173,213-205 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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4943123 |
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Apr 1974 |
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JP |
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03502279 |
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May 1991 |
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JP |
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09232164 |
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Sep 1997 |
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JP |
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2010074132 |
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Apr 2010 |
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JP |
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2010-263238 |
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Nov 2010 |
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JP |
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2013-042028 |
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Feb 2013 |
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JP |
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2013-074084 |
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Apr 2013 |
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JP |
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2014183320 |
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Sep 2014 |
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JP |
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Other References
Unofficial English Translation of Japanese Office Action issued in
connection with corresponding JP Application No. 015206830 dated
Nov. 22, 2016. cited by applicant .
Charley., "Recent Progress in Large Transformers", Journal of the
Institution of Electrical Engineers, vol. No. 59, Issue No. 418,
pp. 1189-1207, Oct. 1931. cited by applicant .
Walker., "The Excitation Requirements of 3-phase Core-type 3-legged
Y-Connected Transformers", AIEEE Transactions, pp. 1113-1119, Dec.
1957. cited by applicant .
Ngnegueu et al., "Zero Phase Sequence Impedance and Tank Heating
Model for Three Phase Three Leg Core Type Power Transformers
Coupling Magnetic Field and Electric Circuit Equations in a Finite
Element Software", IEEE Transactions on Magnetics, vol. No. 31,
Issue No. 03, pp. 2068-2071, May 1995. cited by applicant .
Escarela-Perez et al., "Asymmetry During Load-Loss Measurement of
Three-Phase Three-Limb Transformer", IEEE Transactions on Power
Delivery, vol. No. 22, Issue No. 03, pp. 1566-1574, Jul. 2007.
cited by applicant .
Escarela-Perez et al., "Analytical Description of the Load-Loss
Asymmetry Phenomenon in Three-Phase Three-Limb Transformers", IEEE
Transactions on Power Delivery, vol. No. 24, Issue No. 02, pp.
695-702, Apr. 2009. cited by applicant .
Bhide et al., "Analysis of Five-Legged Transformer Used for
Parallel Operation of Rectifiers by Coupled Circuit-Field
Approach", IEEE Transactions on Power Delivery, vol. No. 26, Issue
No. 02, pp. 607-616, Apr. 2011. cited by applicant .
PCT Search Report and Written Opinion issued in connection with
Related PCT Application No. PCT/US2014/031466 dated Dec. 3, 2014.
cited by applicant .
International Preliminary Report on Patentability issued in
connection with Related PCT Application No. PCT/US2014/031466 dated
Sep. 29, 2016. cited by applicant .
Unofficial English Translation of Chinese Office Action issued in
connection with corresponding CN Application No. 201510714579.2
dated Apr. 19, 2017. cited by applicant .
Unofficial English Translation of Japanese Office Action issued in
connection with corresponding JP Application No. 2015206830 dated
May 16, 2017. cited by applicant .
Second Office Action and Search issued in connection with
corresponding CN Application No. 201510714579.2 dated Oct. 13,
2017. cited by applicant.
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Primary Examiner: Nguyen; Tuyen
Attorney, Agent or Firm: GE Global Patent Operation Kramer;
John A.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application
No. 62/069,946, which was filed on 29 Oct. 2014, and the entire
disclosure of which is incorporated by reference.
Claims
What is claimed is:
1. An electronic filter assembly comprising: a magnetically
conductive outer annular body extending around a center axis; a
magnetically conductive inner annular body extending around the
center axis between the outer annular body and the center axis; a
first set of magnetically conductive prongs radially extending from
the inner annular body toward the outer annular body, wherein the
prongs in the first set are directly coupled with the inner annular
body but are separated from the outer annular body by one or more
first separation gaps; a second set of magnetically conductive
prongs radially extending from the outer annular body toward the
inner annular body, wherein the prongs in the second set are
directly coupled with the outer annular body but are separated from
the inner annular body by one or more second separation gaps; and
conductive windings extending around the prongs in the first
set.
2. The electronic filter assembly of claim 1, wherein the first set
of the magnetically conductive prongs is positioned relative to the
conductive windings and the outer annular body such that the first
set of the magnetically conductive prongs magnetically conduct a
magnetic flux to the outer annular body, the magnetic flux being
induced in the first set of the magnetically conductive prongs by
an electric current being conducted through the conductive
windings.
3. The electronic filter assembly of claim 1, wherein the
magnetically conductive prongs in the first set are symmetrically
separated from each other around the center axis.
4. The electronic filter assembly of claim 1, wherein the inner
annular body extends around a gap through which the center axis
passes such that the center axis does not pass through the inner
annular body.
5. The electronic filter assembly of claim 1, wherein the prongs in
the second set do not include any conductive windings extending
around the prongs in the second set.
6. The electronic filter assembly of claim 1, wherein the first set
of the magnetically conductive prongs is positioned such that the
prongs in the first set magnetically conduct a magnetic flux during
a differential mode of operation of the filter assembly and the
second set of the magnetically conductive prongs is positioned such
that the prongs in the second set magnetically conduct the magnetic
flux during a common mode of operation of the filter assembly.
7. The electronic filter assembly of claim 1, wherein the
magnetically conductive prongs in the first set are symmetrically
separated from each other around the center axis and the
magnetically conductive prongs in the second set are symmetrically
separated from each other around the center axis.
8. The electronic filter assembly of claim 1, wherein the annular
body and the magnetically conductive prongs in the first set are
positioned to magnetically conduct the magnetic flux during a
differential operational mode while the magnetically conductive
prongs in the second set are positioned to not magnetically conduct
the magnetic flux to prevent the magnetic flux from leaking outside
of the annular body and the magnetically conductive prongs in the
first set.
9. The electronic filter assembly of claim 1, wherein the outer
annular body does not include any conductive windings extending
around the outer annular body.
10. An electronic filter assembly comprising: a magnetically
conductive outer annular body extending around a center axis; a
magnetically conductive inner annular body extending around the
center axis between the center axis and the outer annular body; a
first set of magnetically conductive prongs radially extending from
the center axis toward the outer annular body, the prongs in the
first set being separated from the outer annular body by first
separation gaps but directly coupled with the inner annular body;
and a second set of magnetically conductive prongs radially
extending from the center axis toward the outer annular body, the
prongs in the second set being directly coupled with the outer
annular body but separated from the inner annular body by second
separation gaps, and wherein the first set of the magnetically
conductive prongs are positioned to magnetically conduct a magnetic
flux during a differential mode of operation of the filter assembly
and the second set of the magnetically conductive prongs are
positioned to magnetically conduct the magnetic flux during a
common mode of operation of the filter assembly.
11. The electronic filter assembly of claim 10, wherein the
magnetically conductive prongs in the first set are symmetrically
separated from each other around the center axis and the
magnetically conductive prongs in the second set are symmetrically
separated from each other around the center axis.
12. The electronic filter assembly of claim 10, wherein the
magnetically conductive prongs in the first set and in the second
set are positioned to magnetically conduct the magnetic flux during
conduction of a three phase electric current through the conductive
windings.
13. The electronic filter assembly of claim 10, wherein the outer
annular body and the magnetically conductive prongs in the first
set are positioned to magnetically conduct the magnetic flux during
the differential mode and during the common mode to prevent the
magnetic flux from leaking outside of the outer annular body and
the magnetically conductive prongs.
14. An electronic filter assembly comprising: a magnetically
conductive outer annular body extending around a center axis; a
magnetically conductive inner annular body extending around the
center axis between the outer annular body and the center axis; a
first set of magnetically conductive prongs radially extending from
the center axis toward the outer annular body, the first set of
prongs directly coupled with the inner annular body but not
directly coupled with the outer annular body; and a second set of
magnetically conductive prongs radially extending from the center
axis toward the outer annular body, the second set of prongs
directly coupled with the outer annular body but not directly
coupled with the inner annular body, wherein the first set of the
magnetically conductive prongs is positioned to magnetically
conduct a magnetic flux during a differential mode of operation of
the filter assembly and the second set of the magnetically
conductive prongs is positioned to magnetically conduct the
magnetic flux during a common mode of operation of the filter
assembly; and wherein the magnetically conductive prongs in the
first set are symmetrically separated from each other around the
center axis and the magnetically conductive prongs in the second
set are symmetrically separated from each other around the center
axis.
15. The electronic filter assembly of claim 14, wherein the
magnetically conductive prongs in the first set and in the second
set are positioned to magnetically conduct the magnetic flux during
conduction of a three phase electric current through the conductive
windings.
16. The electronic filter assembly of claim 14, wherein the outer
annular body and the magnetically conductive prongs are positioned
to magnetically conduct the magnetic flux during the differential
mode and during the common mode to prevent the magnetic flux from
leaking outside of the annular body and the magnetically conductive
prongs.
17. The electronic filter assembly of claim 1, wherein the one or
more first separation gaps and the one or more second separation
gaps are entirely filled with air.
18. The electronic filter assembly of claim 1, wherein the one or
more first separation gaps and the one or more second separation
gaps are entirely filled with a dielectric material other than
air.
19. The electronic filter assembly of claim 1, wherein each of the
prongs in the first set has a larger cross-sectional area than each
of the prongs in the second set.
20. The electronic filter assembly of claim 1, wherein each of the
prongs in the first set includes several layers of magnetically
conductive material with each of the layers in each of the prongs
has a different shape than an adjacent layer or adjacent layers in
the same prong.
21. The electronic filter assembly of claim 10, wherein the one or
more first separation gaps and the one or more second separation
gaps are entirely filled with air.
22. The electronic filter assembly of claim 10, wherein the one or
more first separation gaps and the one or more second separation
gaps are entirely filled with a dielectric material other than
air.
23. The electronic filter assembly of claim 10, wherein each of the
prongs in the first set has a larger cross-sectional area than each
of the prongs in the second set.
24. The electronic filter assembly of claim 10, wherein each of the
prongs in the first set includes several layers of magnetically
conductive material with each of the layers in each of the prongs
has a different shape than an adjacent layer or adjacent layers in
the same prong.
Description
FIELD
Embodiments of the subject matter disclosed herein relate to
electronic filter assemblies, such as inverters, transformers, or
the like.
BACKGROUND
Some electronic filter assemblies used for multi-phase electric
currents include transformers, inductors, and the like. These
assemblies can include vertically oriented and parallel ferrite
limbs joined by horizontally oriented and parallel ferrite yokes.
Conductive wires are wound around the vertical limbs to form the
assemblies. During operation, electric current is conducted by some
of these windings to induce magnetic flux in the ferrite limbs and
yokes. This flux can be conducted through the yokes to other limbs,
where the flux can induce another current in the wires. This other
current can be a current that is filtered or otherwise transformed
by the assembly before being conducted to one or more loads.
Due to the vertical orientation of the limbs, these types of filter
assemblies may not be magnetically symmetric. For example,
different magnetic fluxes induced in different limbs may be
conducted different distances and/or along different paths. This
can cause an uneven temperature or heating distribution in the
limbs and yokes, which may lead to decreased service life or damage
to the filter assemblies. Additionally, because the yokes typically
are relatively large in order to be coupled with the limbs, the
filter assemblies may be large and heavy.
The asymmetric filter assemblies also can cause significant
increases in impedance and/or leakage of magnetic flux from the
assemblies during common mode operation. For example, when the
asymmetric filter assemblies are used to conduct a common mode
magnetic flux, the common mode flux may not be able to be conducted
through the yokes to the other limbs. As a result, impedance of the
filter assemblies increase significantly and/or the common mode
flux leaks from the limbs and yokes of the filter assemblies.
BRIEF DESCRIPTION
In one embodiment, an electronic filter assembly includes a
magnetically conductive annular body extending around a center
axis, a first set of magnetically conductive prongs radially
extending from the center axis toward the annular body, and
conductive windings extending around the prongs in the first
set.
In another embodiment, a method (e.g., for forming an electronic
filter assembly) includes forming an electronic filter assembly
having a magnetically conductive annular body extending around a
center axis and a first set of magnetically conductive prongs
radially extending from the center axis toward the annular body.
The annular body and the prongs can be formed by coupling plural
layers of magnetically conductive bodies together. The prongs are
configured to receive conductive windings extending around the
prongs to form the electronic filter assembly.
In another embodiment, another electronic filter assembly includes
a magnetically conductive annular body extending around a center
axis, a first set of magnetically conductive prongs radially
extending from the center axis toward the annular body, and a
second set of magnetically conductive prongs radially extending
from the center axis toward the annular body. The first set of the
magnetically conductive prongs are configured to magnetically
conduct a magnetic flux during a differential mode of operation of
the filter assembly and the second set of the magnetically
conductive prongs are configured to magnetically conduct the
magnetic flux during a common mode of operation of the filter
assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is made to the accompanying drawings in which particular
embodiments and further benefits of the invention are illustrated
as described in more detail in the description below, in which:
FIG. 1 is a perspective view of a symmetric filter assembly
according to one embodiment;
FIG. 2 is a schematic diagram of the filter assembly shown in FIG.
1;
FIG. 3 illustrates another filter assembly according to another
embodiment;
FIG. 4 is a schematic diagram of the filter assembly shown in FIG.
3;
FIG. 5 illustrates a cross-sectional view of a filter assembly
according to another embodiment;
FIG. 6 schematically illustrates conduction of magnetic flux
(.PHI.) in the filter assembly during a differential mode operation
of the filter assembly according to one embodiment;
FIG. 7 schematically illustrates conduction of magnetic flux
(.PHI.) in the filter assembly during a common mode operation of
the filter assembly according to one embodiment;
FIG. 8 illustrates several layers of material that may be combined
to form the filter assembly shown in FIG. 1 according to one
embodiment;
FIG. 9 illustrates a flowchart of a method for forming an
electronic filter assembly according to one embodiment; and
FIG. 10 illustrates a cross-sectional view of a filter assembly
according to one embodiment.
DETAILED DESCRIPTION
One or more embodiments of the assemblies and methods described
herein provide symmetric common-mode structures for filter
assemblies, such as for filters used in power-electronics
inverters. The assemblies described herein can be relatively easy
to manufacture and can provide compact, light-weight, and/or lower
cost filters relative to some known core-type filters.
FIG. 1 is a perspective view of a symmetric filter assembly 100
according to one embodiment. FIG. 2 is a schematic diagram of the
filter assembly 100 shown in FIG. 1. FIG. 2 illustrates the flow of
magnetic flux through the filter assembly 100. The filter assembly
100 includes an annular yoke or core body 102 that extends around
(e.g., encircles) a center axis 104. The core body 102 may have a
non-circular shape as shown in FIG. 1, may have a circular shape,
or may have another shape. The core body 102 can be formed from a
magnetically conductive material, such as a ferrite material. The
filter assembly 100 also includes plural prongs 106 that radially
extend along directions extending from the center axis 104 toward
the core body 102. The prongs 106 also can be formed from a
magnetically conductive material, such as a ferrite material. The
prongs 106 can be coupled with the core body 102 and with each
other, as shown in FIG. 1, or may be separated from the core body
102 and/or each other by one or more separation gaps, as described
below.
The prongs 106 may be symmetrically disposed around the center axis
104. For example, the prongs 106 may be separated from each other
by
##EQU00001## degrees, by
.times..pi. ##EQU00002## radians, or by another distance, where n
represents the number of prongs 106. In the illustrated embodiment,
three prongs 106 are included, but alternatively, another number of
prongs 106 may be provided. The prongs 106 are at least partially
surrounded by conductive windings 108. The conductive windings 108
can conduct different phases of an electric current to induce
magnetic fluxes in the prongs 106. For example, the conductive
windings 108 around a first prong 106 can electrically conduct a
first phase (e.g., "A-phase" in FIG. 1) of an alternating current,
a different, second prong 106 can electrically conduct a different,
second phase (e.g., "B-phase" in FIG. 1) of the same alternating
current, and a different, third prong 106 can electrically conduct
a different, third phase (e.g., "C-phase" in FIG. 1) of the same
alternating current.
During conduction of a first phase of the electric current through
the conductive windings 108 extending around a prong 106 (e.g., the
A-phase and the first prong 106 as shown in FIG. 1), a magnetic
flux (.PHI.) is induced in the prong 106. FIG. 2 illustrates
several flux lines 200 representative of the magnetic flux (.PHI.)
in the filter assembly 100. The spacing between the flux lines 200
can indicate the density of the magnetic flux (.PHI.), such as
where closer lines 200 represent increased flux density relative to
lines 200 that are farther apart. As the flux (.PHI.) is conducted
along the prong 106, the flux (.PHI.) can be divided into partial
fluxes (e.g.,
.PHI..times. ##EQU00003## and be conducted through the core body
102. Other prongs 106 can conduct other magnetic fluxes (.PHI.)
into the core body 102 in similar manner as what is shown in FIG. 2
for a single prong 106.
The windings 108 around each prong 106 can represent different sets
of conductive windings. For example, the conductive windings 108
around one prong 106 can represent a first winding and a second
winding of conductive material (e.g., wires), with the first
winding and the second windings being separate from each other and
not conductively coupled with each other. One of these windings can
conduct a current to induce the magnetic flux (.PHI.) in the prong
106. The other winding may conduct a current that is generated
based on the magnetic flux (.PHI.) being conducted through the same
prong 106. For example, a current may be induced in the second
winding by the magnetic flux (.PHI.). The current that is conducted
through the first winding to induce the magnetic flux (.PHI.) can
be referred to as an input or incoming current and the current that
is induced in the second winding from the magnetic flux (.PHI.) can
be referred to as an output or outgoing current. The filter
assembly 100 may receive electric current into the first windings
around the prongs 106 and remove portions of this current (e.g., by
filtering out spikes or sudden increases in the current) by
inducing the magnetic flux (.PHI.) in the prongs 106 and core body
102 of the filter assembly 100 and then inducing the output current
in the second windings from the magnetic flux (.PHI.). Optionally,
the filter assembly 100 can be used as a transformer, inductor, or
the like, that increases, decreases, or otherwise changes a voltage
or other magnitude of the current that is conducted into the first
windings to the output current that is induced in the second
windings.
As shown in FIGS. 1 and 2, the prongs 106 and core body 102 of the
filter assembly 100 are symmetrically disposed about the center
axis 104. This symmetric arrangement of the filter assembly 100 can
provide for a more uniform temperature distribution throughout the
filter assembly 100. For example, during conduction of larger
currents through the conductive windings 108, relatively large
magnetic fluxes (.PHI.) can be induced and conducted through the
prongs 106 and core body 102. These fluxes (.PHI.) can
significantly increase the temperature of the prongs 106 and core
body 102. Because the prongs 106 and core body 102 form a symmetric
shape about the center axis 104, the distribution of temperature
increases can be evenly distributed throughout the prongs 106 and
core body 102. If the prongs 106 were not evenly spaced about the
center axis 104 and/or if the core body 102 has another,
non-symmetric shape around the center axis 104, then the
temperature increase in one or more portions of the filter assembly
100 may be significantly greater than the temperature increases in
one or more other portions of the filter assembly 100. Such
localized heating can increase the wear and tear, and/or increase
the probability of failure, at or near the portions having the
larger temperature increases. By evenly distributing the
temperature increases, the filter assembly 100 can have a longer
service life before repair and/or replacement is needed relative to
an asymmetric filter assembly.
The symmetric shape of the filter assembly 100 also can reduce the
weight of the filter assembly 100 relative to asymmetric shapes.
Asymmetric shapes of filters can involve extra material that is not
efficiently used to conduct magnetic flux (.PHI.) in the ferrite
materials of the filters. The symmetric shape of the filter
assembly 100 can reduce the amount of extra ferrite material that
is included in the prongs 106 and/or core body 102 without
sacrificing the conduction of magnetic flux (.PHI.) in the filter
assembly 100 relative to heavier, asymmetric filters. The reduced
amount of materials also may reduce the cost and/or size of the
filter assembly 100 relative to asymmetric filters.
FIG. 3 illustrates another filter assembly 300 according to another
embodiment. Similar to the filter assembly 100 shown in FIGS. 1 and
2, the filter assembly 300 includes an annular yoke or core body
302 that extends around (e.g., encircles) a center axis 304. FIG. 4
is a schematic diagram of the filter assembly 300 shown in FIG. 3.
FIG. 4 illustrates the flow of magnetic flux through the filter
assembly 300. The center axis 304 is shown as a point in FIG. 3
because the center axis 304 is oriented perpendicular to the plane
of FIG. 3. The core body 302 may have a circular shape as shown in
FIG. 3, may have a non-circular shape, or may have another shape.
The core body 302 can be formed from a magnetically conductive
material, such as a ferrite material.
The filter assembly 300 also includes plural prongs 306 that
radially extend along directions extending from the center axis 304
toward the core body 302. In contrast to the prongs 106 shown in
FIG. 1 that meet at the center axis 104 shown in FIGS. 1 and 2, the
prongs 306 shown in FIG. 3 do not meet at the center axis 304.
Instead, the prongs 306 extend to an inner annular section 308 of
the filter assembly 300 that extends around or encircles an air gap
or separation gap 310. The inner annular section 308 may be formed
from the same or similar material as the core body 302 and/or
prongs 306. The center axis 304 is disposed within the gap 310
inside the inner annular section 308. The prongs 306 are coupled
with the inner annular section 308 such the prongs 306 and inner
annular section 308 are continuous (e.g., not separated by a gap).
Alternatively, one or more gaps may be disposed between the prongs
306 and the inner annular section 308.
Also in contrast to the filter assembly 100 shown in FIGS. 1 and 2,
the filter assembly 300 includes separation gaps 310 between the
prongs 306 and the core body 302. The separation gaps 310 may be
air gaps or may be spaces that are completely or at least partially
filled with a material, such as a dielectric material. The prongs
306 also can be formed from a magnetically conductive material,
such as a ferrite material.
Similar to the prongs 106 shown in FIGS. 1 and 2, the prongs 306
may be symmetrically disposed around the center axis 304. In the
illustrated embodiment, three prongs 306 are included, but
alternatively, another number of prongs 306 may be provided. The
prongs 306 are at least partially surrounded by conductive windings
108 similar or identical to the prongs 106 of the filter assembly
100 shown in FIGS. 1 and 2. The conductive windings 108 can conduct
different phases of an electric current to induce magnetic fluxes
in the prongs 306, similar to as described above.
During conduction of a first phase of the electric current through
the conductive windings 108 extending around a first prong 306, a
magnetic flux (.PHI.) may be induced in the first prong 306. As the
flux (.PHI.) is conducted along the first prong 306, the flux
(.PHI.) can be divided into partial fluxes (e.g.,
.PHI..times. ##EQU00004## and be conducted across the separation
gap 310 and into the core body 302. Other prongs 306 can conduct
other magnetic fluxes (.PHI.) into the core body 302 in similar
manner. Several magnetic flux lines 200 shown in FIG. 4 illustrate
the density of magnetic flux (.PHI.) being conducted and/or induced
in the prongs 306 and core body 302.
As shown in FIG. 3, the prongs 306 and core body 302 of the filter
assembly 300 are symmetrically disposed about the center axis 304.
This symmetric arrangement of the filter assembly 300 can provide
for a more uniform temperature distribution throughout the filter
assembly 300, and/or reduced weight, cost, and/or size of the
filter assembly 300 relative to asymmetric filters.
FIG. 5 illustrates a cross-sectional view of a filter assembly 500
according to another embodiment. Similar to the filter assemblies
100, 300 shown in FIGS. 1 through 4, the filter assembly 500
includes an annular yoke or core body 502 that extends around
(e.g., encircles) a center axis 504. The center axis 504 is shown
as a point in FIG. 5 because the center axis 504 is oriented
perpendicular to the plane of FIG. 5. The core body 502 may have a
circular shape as shown in FIG. 5, may have a non-circular shape,
or may have another shape. The core body 502 can be formed from a
magnetically conductive material, such as a ferrite material.
Similar to the filter assemblies 100, 300, the filter assembly 500
also includes several prongs that radially extend along directions
extending from the center axis 504 toward the core body 502. In
contrast to the filter assemblies 100, 300, the filter assembly 500
includes plural sets of the prongs. A first set of the prongs
includes differential mode prongs 506 (e.g., prongs 506A-C) and
another set of the prongs includes common mode prongs 508 (e.g.,
prongs 508A-C). While three prongs 506 and three prongs 508 are
shown, alternatively, one or more of the differential mode prongs
506 and/or the common mode prongs 508 may include a lesser or
greater number of prongs 506, 508. As shown in FIG. 5, the
differential mode prongs 506 may be larger than the common mode
prongs 508, such as by a cross-sectional diameter, perimeter, area,
or other measurement of the differential mode prongs 506 being
greater than a corresponding cross-sectional diameter, perimeter,
area, or other measurement of the common mode prongs 508. The
prongs 506, 508 also can be formed from a magnetically conductive
material, such as a ferrite material.
Similar to the prongs 306 of the filter assembly 300 shown in FIG.
3, the prongs 506 shown in FIG. 5 do not meet at the center axis
504. The prongs 506 may extend to an inner annular section 510 of
the filter assembly 500, which can be formed from the same or
similar material as the prongs 506 and/or the core body 502. The
inner annular section 510 may be continuous with the prongs 506
such that no gap or separation exists between the prongs 506 and
the inner annular section 510, similar to the prongs 306 and the
inner annular section 308 shown in FIG. 3. Alternatively, one or
more gaps may be disposed between the prongs 506 and the inner
annular section 510. The inner annular section 510 extends around
or encircles an air gap or separation gap 512. The center axis 504
is disposed within the gap 512 inside the inner annular section
510.
Separation gaps 514 may be disposed between the differential mode
prongs 506 and the core body 502. The separation gaps 514 may be
air gaps or may be spaces that are completely or at least partially
filled with a material, such as a dielectric material.
Alternatively, the differential mode prongs 506 can be coupled with
or continuous with the core body 502 such that no gaps exist
between the differential mode prongs 506 and the core body 502.
The common mode prongs 508 may be separated from the inner annular
section 510 of the filter assembly 500 by separation gaps 516. The
separation gaps 516 may be air gaps or may be spaces that are
completely or partially filled with a material, such as a
dielectric material. Alternatively, the common mode prongs 508 can
be coupled with or continuous with the inner annular section 510
such that no gaps exist between the common mode prongs 508 and the
inner annular section 510.
Similar to the prongs 106, 306 shown in FIGS. 1 through 4, the
prongs 506 and the prongs 508 may be symmetrically disposed around
the center axis 504. In the illustrated embodiment, each of the
common mode prongs 508 is disposed between two differential mode
prongs 506 and each of the differential mode prongs 506 is disposed
between two common mode prongs 508. For example, the order of the
prongs 506, 508 may alternate along a clockwise or
counter-clockwise path around the center axis 504.
The differential mode prongs 506 are at least partially surrounded
by conductive windings 108 similar or identical to the prongs 106,
306 of the filter assemblies 100, 300 shown in FIGS. 1 through 4.
The conductive windings 108 can conduct different phases of an
electric current to induce magnetic fluxes in the prongs 506 and/or
to conduct output currents induced by the magnetic fluxes, similar
to as described above. For example, the windings 108 around the
prong 506A can conduct a first phase of an alternating current to
induce a first magnetic flux (.PHI..sub.1) in the prong 506A, the
windings 108 around the prong 506B can conduct a second phase of
the alternating current to induce a second magnetic flux
(.PHI..sub.2) in the prong 506B, and the windings 108 around the
prong 506C can conduct a third phase of the alternating current to
induce a third magnetic flux (.PHI..sub.3) in the prong 506C. The
windings 108 also can conduct an output current that is induced in
the windings 108 by the magnetic fluxes (.PHI..sub.1, .PHI..sub.2,
.PHI..sub.3)
During different modes of operation of the filter assembly 500,
different magnetic fluxes (.PHI.) can be induced in the prongs 506
and/or 508. For example, during a differential mode operation of
the filter assembly 500, magnetic fluxes (.PHI.) may be induced in
the differential mode prongs 506 and conducted by the differential
mode prongs 506 to the core body 502 and/or other prongs 506, but
may not be induced in and/or conducted to the common mode prongs
508. During a common mode operation of the filter assembly 500,
magnetic fluxes (.PHI.) may be induced and/or conducted by both the
differential mode prongs 506 and the common mode prongs 508.
FIG. 6 schematically illustrates conduction of magnetic flux
(.PHI.) in the filter assembly 500 during a differential mode
operation of the filter assembly 500 according to one embodiment.
As shown by the flux lines 200 representative of the magnetic flux
(.PHI.) in the prongs and core body of the filter assembly 500, the
magnetic flux (.PHI.) is induced in the differential mode prongs
506 but not in the common mode prongs 508 when the current is
conducted through the windings 108 to the filter assembly 500 in a
differential mode. This flux (.PHI.) is relatively dense in the
differential mode prongs 506 and can be conducted across the gaps
514 into the core body 502. As described above, parts of the
windings 108 may conduct the differential mode current to generate
the magnetic flux (.PHI.), while separate other parts of the
windings 108 may conduct an output current that is induced by the
magnetic flux (.PHI.) out of the filter assembly 500.
FIG. 7 schematically illustrates conduction of magnetic flux
(.PHI.) in the filter assembly 500 during a common mode operation
of the filter assembly 500 according to one embodiment. As shown by
the flux lines 200 representative of the magnetic flux (.PHI.) in
the prongs and core body of the filter assembly 500, the magnetic
flux (.PHI.) is induced in the differential mode prongs 506 and in
the common mode prongs 508 when the current is conducted through
the windings 108 to the filter assembly 500 in a common mode. This
flux (.PHI.) is induced in the common mode prongs 508 even though
the windings 108 that conduct the current that induces the magnetic
flux (.PHI.) do not extend around the common mode prongs 508 in one
embodiment.
As described above, the prongs 506, 508 and core body 508 of the
filter assembly 500 are symmetrically disposed about the center
axis 504. This symmetric arrangement of the filter assembly 500 can
provide for a more uniform temperature distribution throughout the
filter assembly 500, and/or reduced weight, cost, and/or size of
the filter assembly 500 relative to asymmetric filters.
Additionally, the common mode prongs 508 can be provided to conduct
the magnetic flux (.PHI.) induced by common mode current through
the filter assembly 500. By conducting the magnetic flux (.PHI.)
induced by both differential and common modes of operation, very
little or no magnetic flux (.PHI.) may leak out of the filter
assembly 500. Instead, substantially all or all of the magnetic
flux (.PHI.) may be used to induce the output current that is
conducted out of the filter assembly 500 by the windings 108.
In one aspect, the common mode prongs 508 provide paths for common
mode flux only. These prongs 508 can be saturated with magnetic
flux and/or the symmetric locations of the prongs 508 can cancel
some of the flux being carried by the prongs 508 such that the
prongs 508 do not contribute any inductance to the filter assembly
500. While in case of zero-sequence flux (or common mode flux),
common mode flux cannot complete a path from the prongs 506 and
therefore can be conducted through the prongs 508.
For example, in a situation where an R-phase of magnetic flux is
maximum (e.g., (.PHI..sub.m), the Y-phase and B-phase of the
magnetic flux can each be
.PHI. ##EQU00005## The flux induced in any of the prongs 506 can be
conducted along a path from the other two prongs 506 with very
little flux being conducted through the common mode prongs 508. At
the time of a zero-phase sequence flux (e.g., a common mode flux or
common mode operation, where the magnetic flux is identical in
phase and magnitude), the flux cannot be conducted along a path
through the differential mode prongs 506. Because the common mode
prongs 508 are symmetrically positioned around the center axis 504,
this common mode flux can be conducted through the common mode
prongs 508 and high inductance provided to this common mode
flux.
One or more of the filter assemblies described herein can be formed
according to a laminate assembly method. Such a method can include
combining multiple layers of material (e.g., ferrite material) used
to form the core and prongs of the filter assembly. The layers can
be combined by placing an adhesive material between abutting
layers, by melting, welding, or otherwise fusing abutting layers
together, or the like, until the core body and prongs are formed.
The conductive windings can then be wound around the prongs, as
described herein.
FIG. 10 illustrates a cross-sectional view of a filter assembly
1000 according to one embodiment. The filter assembly 1000 can
represent one or more of the filter assemblies described herein,
such as the filter assembly 100, 300, and/or 500. The filter
assembly 1000 includes an annular yoke or core body 1002 that
extends around (e.g., encircles) a center axis 1004. The center
axis 1004 is shown as a point in FIG. 10 because the center axis
1004 is oriented perpendicular to the plane of FIG. 10. The filter
assembly 1000 also includes several prongs that radially extend
along directions extending from the center axis 1004 toward the
core body 1002. In the illustrated embodiment, the filter assembly
1000 includes a first set of prongs 1006 (e.g., differential mode
prongs) and a second set of prongs 1008 (e.g., common mode prongs).
Alternatively, the filter assembly 1000 may include the prongs 1006
but not the prongs 1008, or may include the prongs 1008 but not the
prongs 1006.
The prongs 1006 do not meet at the center axis 1004. The prongs
1006 may extend to an inner annular section 1010 of the filter
assembly 1000. The inner annular section 1010 may be continuous
with the prongs 1006 such that no gap or separation exists between
the prongs 1006 and the inner annular section 1010. Alternatively,
one or more gaps may be disposed between the prongs 1006 and the
inner annular section 1010. The inner annular section 1010 extends
around or encircles an air gap or separation gap 1012. The center
axis 1004 is disposed within the gap 1012 inside the inner annular
section 1010. Separation gaps 1014 may be disposed between the
prongs 1006 and the core body 1002. Alternatively, the prongs 1006
can be coupled with or continuous with the core body 1002 such that
no gaps exist between the prongs 1006 and the core body 1002. The
prongs 1008 may be separated from the inner annular section 1008 by
separation gaps, similar to the gaps 516 shown in FIG. 5.
Alternatively, the prongs 1008 can be coupled with or continuous
with the inner annular section 1010 such that no gaps exist between
the common mode prongs 1008 and the inner annular section 1010. The
prongs 1006 may be at least partially surrounded by conductive
windings similar to as described herein for other assemblies.
The prongs 1006 and the prongs 1008 may be symmetrically disposed
around the center axis 1004. Arcs 1016 having the same length may
extend between neighboring prongs 1006 of the first set of prongs
1006. Arcs 1018 having the same length may extend between
neighboring prongs 1008 of the second set of prongs 1008. Only one
of each of the arcs 1016, 1018 is shown in FIG. 10 for purposes of
clarity. These arcs 1016, 1018 may extend along paths defined by
circumferences of one or more circles having a center that is
coextensive (e.g., the same as) the center axis 1004. In one
embodiment, the arcs 1016, 1018 may extend along a path defined by
the circumference of the same circle having a center that is the
same as the center axis 1004. The length of the arcs 1016 may all
be the same and the length of the arcs 1018 may all be the same.
The length of the arcs 1016 may be the same as the length of the
arcs 1018 in one embodiment. Alternatively, the length of the arcs
1016 may differ from the length of the arcs 1018 (e.g., where there
are more prongs 1006 than prongs 1008 or more prongs 1008 than
prongs 1006).
The prongs 1006 are symmetrically disposed around the center axis
1004 by being spaced apart from each other by the same distances
(e.g., the arcs 1016) that extend around the center axis 1004. The
prongs 1008 are symmetrically disposed around the center axis 1004
by being spaced apart from each other by the same distances (e.g.,
the arcs 1018) that extend around the center axis 1004.
FIG. 8 illustrates several layers 1-6 of material that may be
combined to form the filter assembly 100 shown in FIG. 1 according
to one embodiment. While the description of the fabrication method
focuses on the filter assembly 100, optionally, this same method
can be used to form one or more other filter assemblies 300, 500
described herein.
In one embodiment, the layers can be formed from several separate
bodies of ferrite material or another magnetically conductive
material. These bodies can be coupled with each other, such as by
using an adhesive, by welding, fusing, or otherwise connecting the
bodies. The bodies used to form the same part of the filter
assembly 100 in different layers 1-6 can be differently shaped.
For example, the bodies 800, 802, 804, 806, 808, 810 in layer 1
form the core body 102. These bodies differ in shape from the
bodies 818, 820, 822, 824, 826, 828 in the layer 2 that form the
corresponding portions of the core body 102. Additionally, the
bodies 812, 814, 816 that form parts of the prongs 106 in the layer
1 can be differently shaped from the bodies 830, 832, 834 in the
layer 2. As shown in FIG. 8, other layers 3-6 can have differently
shaped bodies that form different parts of the core body 102 and/or
prongs 106. These different layers 1-6 with the differently shaped
bodies can be coupled together to form the core body 102 and the
prongs 106.
FIG. 9 illustrates a flowchart of a method 900 for forming an
electronic filter assembly according to one embodiment. The method
900 may be used to form one or more of the filter assemblies
described herein. At 902, plural layers of magnetically conductive
bodies are obtained. These layers may be cut or otherwise obtained
from a larger body of a magnetically conductive material. For
example, the smaller bodies shown in FIG. 8 may be cut from a
magnetically conductive material and then joined together by
adhesives, welding, fusing, or the like, to form the multiple
layers 1-6 shown in FIG. 8. At 904, the layers are coupled together
to form an annular body with prongs. For example, the layers 1-6
shown in FIG. 8 may be joined together using adhesive, welding,
fusing, or the like, to form one or more of the annular bodies and
prongs shown and described herein. At 906, conductive windings are
placed around the prongs to form an electronic filter assembly. For
example, the windings 108 may be wound around the prongs 106, 306,
506 to form one or more of the filter assemblies described
herein.
In one embodiment, an electronic filter assembly includes a
magnetically conductive annular body extending around a center
axis, a first set of magnetically conductive prongs radially
extending from the center axis toward the annular body, and
conductive windings extending around the prongs in the first
set.
In one aspect, the first set of the magnetically conductive prongs
is configured to magnetically conduct a magnetic flux to the
annular body. The magnetic flux can be induced in the first set of
the magnetically conductive prongs by an electric current being
conducted through the conductive windings.
In one aspect, the magnetically conductive prongs in the first set
are symmetrically separated from each other around the center axis.
For example, in a plane that is perpendicular to the center axis,
the prongs in the first set may be separated from each other by
arcs disposed in the same plane and extending from each prong to a
neighboring prong in the first set, with the lengths of the arcs
being the same between any two neighboring prongs of the prongs in
the first set.
In one aspect, the prongs in the first set are separated from the
annular body by one or more separation gaps.
In one aspect, the filter assembly also includes an inner annular
section that extends around a gap through which the center axis
passes. The prongs can extend from the inner annular section toward
the annular body.
In one aspect, the filter assembly also includes a second set of
magnetically conductive prongs radially extending from the center
axis toward the annular body.
In one aspect, the prongs in the second set do not include any
conductive windings extending around the prongs.
In one aspect, the annular body does not include any conductive
windings extending around the annular body.
In one aspect, the first set of the magnetically conductive prongs
is configured to magnetically conduct a magnetic flux during a
differential mode of operation of the filter assembly and the
second set of the magnetically conductive prongs are configured to
magnetically conduct the magnetic flux during a common mode of
operation of the filter assembly.
In one aspect, the magnetically conductive prongs in the first set
are symmetrically separated from each other around the center axis
and the magnetically conductive prongs in the second set are
symmetrically separated from each other around the center axis. For
example, in a plane that is perpendicular to the center axis, the
prongs in the first set may be separated from each other by first
arcs disposed in the same plane and extending from each prong to a
neighboring prong in the first set and the prongs in the second set
may be separated from each other by second arcs disposed in the
same plane and extending from each prong to a neighboring prong,
with the lengths of the first arcs being the same between any two
neighboring prongs of the prongs in the first set and the lengths
of the second arcs being the same between any two neighboring
prongs of the prongs in the second set.
In one aspect, the magnetically conductive prongs in the first set
and in the second set are configured to magnetically conduct the
magnetic flux during conduction of a three phase electric current
through the conductive windings.
In one aspect, the magnetically conductive prongs in the first set
are separated from the annular body by separation gaps and the
magnetically conductive prongs in the second set are connected with
the annular body.
In one aspect, the annular body and the magnetically conductive
prongs in the first set magnetically conduct the magnetic flux
during a differential operational mode while the magnetically
conductive prongs in the second set do not magnetically conduct the
magnetic flux to prevent the magnetic flux from leaking outside of
the annular body and the magnetically conductive prongs in the
first set.
In another embodiment, a method (e.g., for forming an electronic
filter assembly) includes forming an electronic filter assembly
having a magnetically conductive annular body extending around a
center axis and a first set of magnetically conductive prongs
radially extending from the center axis toward the annular body.
The annular body and the prongs can be formed by coupling plural
layers of magnetically conductive bodies together. The prongs are
configured to receive conductive windings extending around the
prongs to form the electronic filter assembly.
In one aspect, the magnetically conductive bodies in the layers
have different shapes.
In one aspect, the magnetically conductive bodies in the layers
that form a common component of the annular body or the prongs have
different shapes in different layers of the layers.
In another embodiment, another electronic filter assembly includes
a magnetically conductive annular body extending around a center
axis, a first set of magnetically conductive prongs radially
extending from the center axis toward the annular body, and a
second set of magnetically conductive prongs radially extending
from the center axis toward the annular body. The first set of the
magnetically conductive prongs are configured to magnetically
conduct a magnetic flux during a differential mode of operation of
the filter assembly and the second set of the magnetically
conductive prongs are configured to magnetically conduct the
magnetic flux during a common mode of operation of the filter
assembly.
In one aspect, the magnetically conductive prongs in the first set
are symmetrically separated from each other around the center axis
and the magnetically conductive prongs in the second set are
symmetrically separated from each other around the center axis.
In one aspect, the filter assembly also includes conductive
windings extending around the magnetically conductive prongs in the
first set.
In one aspect, the magnetically conductive prongs in the first set
and in the second set are configured to magnetically conduct the
magnetic flux during conduction of a three phase electric current
through the conductive windings.
In one aspect, the magnetically conductive prongs in the first set
are separated from the annular body by separation gaps and the
magnetically conductive prongs in the second set are connected with
the annular body.
In one aspect, the annular body and the magnetically conductive
prongs magnetically conduct the magnetic flux during the
differential mode and during the common mode to prevent the
magnetic flux from leaking outside of the annular body and the
magnetically conductive prongs.
It is to be understood that the above description is intended to be
illustrative, and not restrictive. For example, the above-described
embodiments (and/or aspects thereof) may be used in combination
with each other. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
inventive subject matter without departing from its scope. While
the dimensions and types of materials described herein are intended
to define the parameters of the inventive subject matter, they are
by no means limiting and are exemplary embodiments. Many other
embodiments will be apparent to one of ordinary skill in the art
upon reviewing the above description. The scope of the inventive
subject matter should, therefore, be determined with reference to
the appended claims, along with the full scope of equivalents to
which such claims are entitled. In the appended claims, the terms
"including" and "in which" are used as the plain-English
equivalents of the respective terms "comprising" and "wherein."
Moreover, in the following claims, the terms "first," "second," and
"third," etc. are used merely as labels, and are not intended to
impose numerical requirements on their objects. Further, the
limitations of the following claims are not written in
means-plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn.112(f), unless and until such claim
limitations expressly use the phrase "means for" followed by a
statement of function void of further structure.
This written description uses examples to disclose several
embodiments of the inventive subject matter and also to enable a
person of ordinary skill in the art to practice the embodiments of
the inventive subject matter, including making and using any
devices or systems and performing any incorporated methods. The
patentable scope of the inventive subject matter may include other
examples that occur to those of ordinary skill in the art. Such
other examples are intended to be within the scope of the claims if
they have structural elements that do not differ from the literal
language of the claims, or if they include equivalent structural
elements with insubstantial differences from the literal languages
of the claims.
As used herein, an element or step recited in the singular and
proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "an embodiment" or
"one embodiment" of the inventive subject matter are not intended
to be interpreted as excluding the existence of additional
embodiments that also incorporate the recited features. Moreover,
unless explicitly stated to the contrary, embodiments "comprising,"
"including," or "having" an element or a plurality of elements
having a particular property may include additional such elements
not having that property.
Since certain changes may be made in the above-described systems
and methods without departing from the spirit and scope of the
inventive subject matter herein involved, it is intended that all
of the subject matter of the above description or shown in the
accompanying drawings shall be interpreted merely as examples
illustrating the inventive concept herein and shall not be
construed as limiting the inventive subject matter.
As used herein, a structure, limitation, or element that is
"configured to" perform a task or operation is particularly
structurally formed, constructed, programmed, or adapted in a
manner corresponding to the task or operation. For purposes of
clarity and the avoidance of doubt, an object that is merely
capable of being modified to perform the task or operation is not
"configured to" perform the task or operation as used herein.
Instead, the use of "configured to" as used herein denotes
structural adaptations or characteristics, programming of the
structure or element to perform the corresponding task or operation
in a manner that is different from an "off-the-shelf" structure or
element that is not programmed to perform the task or operation,
and/or denotes structural requirements of any structure,
limitation, or element that is described as being "configured to"
perform the task or operation.
* * * * *